Hepatitis A is an acute illness caused by infection with hepatitis A virus (HAV). The virus replicates in the liver, transports through the bile, and is excreted into the feces via the biliary system.1,2

The likelihood of symptomatic illness from HAV is directly linked to age. Although more
than 75% of adults with HAV infection experience symptoms, nearly 70% of children under 6 years of
age are asymptomatic.1,2

For those who experience symptoms, the onset is typically abrupt and includes1,2:

The transmission of HAV infection occurs from person-to-person contact through the fecal-oral route or by consuming contaminated food or drink.1 In very rare instances, the transmission of HAV infection can occur through the use of contaminated blood and blood products.2

Depending upon environmental conditions, HAV can live outside the body for months. Heating
food at temperatures >185oF (>85oC) for
1 minute or disinfecting surfaces with a dilution of household bleach and water (1:100 ratio) can
inactivate HAV; however, the virus is still capable of being spread if food contamination occurs
after cooking.2,3

Waterborne outbreaks of HAV in developed countries are rare; occurrences of this nature are
generally attributed to sewage contamination and inadequately treated water.3

Historically, hepatitis A rates vary cyclically, with nationwide increases every 10-15 years. The last peak was in 1995; since that time, rates of hepatitis A generally declined until 2011. In 2013, a total of 1,781 cases of hepatitis A were reported, a 14% increase from 2012 due to a large outbreak in 2013. The overall incidence rate in 2013 was 0.6 cases per 100,000 population. After adjusting for under-ascertainment and under-reporting, an estimated 3,473 hepatitis A cases occurred in 2013. (Data were unavailable for the District of Columbia.)
4

Centers for Disease Control and Prevention (CDC). Prevention of hepatitis A through active or
passive immunization: Recommendations of the Advisory Committee on Immunization Practices (ACIP).
MMWR Recomm Rep. 2006;55(RR-7):1–23.

Centers for Disease Control and Prevention. Surveillance for viral hepatitis--UnitedStates,2013.
http://www.cdc.gov/hepatitis/Statistics/ 2013Surveillance/Commentary.htm.
Updated April 24,2015. Accessed April 27,2015

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